The invention relates to a heat exchanger housing for at least one heat exchanger for exchanging heat between a first fluid and a second fluid. The invention also relates to a heat exchanger or a modular unit having one or more heat exchangers for exchanging heat between a first fluid and a second fluid. The invention also relates to an exhaust-gas recirculation system, a charge-air supply system and a use of the heat exchanger or of the modular unit.
An exhaust-gas recirculation system or charge-air supply system, in particular with cooled exhaust gas and/or charge air, is used in modern vehicles on account of legal requirements for reducing particles and pollutants, in particular nitrogen oxide emissions. Here, on the one hand, the demands on exhaust-gas purification and the exhaust-gas mass flow rates which must be dealt with increase, and on the other hand, such systems and in particular the heat exchanger developments necessary for this purpose are largely cost-driven.
A heat exchanger serves fundamentally to exchange heat between a first fluid, in particular an exhaust gas in the case of an exhaust-gas cooler or charge air in the case of a charge-air cooler, and a second fluid, in particular a coolant, for example a water-based coolant or some other liquid or gaseous coolant. Exhaust-gas coolers in particular are if appropriate constructed with a bypass pipe in order to reach the operating temperature of an internal combustion engine more quickly. For this purpose, a bypass duct may for example be closed off by means of a flap once the operating temperature of the internal combustion engine has been reached, and a heat exchanger for taking over cooling operation is provided. For example, DE 10 203 003 A1 discloses a single-stage heat exchanger system with an integrated bypass duct and bypass flap. Also known, from DE 600 243 90 T2, is a two-stage system of heat exchangers with an integrated bypass duct with a bypass flap. It is fundamentally known, in order to reduce costs, to integrate a bypass duct and/or a bypass flap, for example as per DE 199 62 863 A1 or DE 198 41 927 A1, in a module together with a heat exchanger. Such systems or modules do however leave room for improvement. Until now, to produce such systems and/or modules, it has been necessary to produce a bypass duct in the form of a bypass pipe separately from the module or the system, and for said bypass duct to be bundled into a heat exchanger housing and subsequently welded to a suitable connecting part of the heat exchanger, for example a base on the block of the heat exchanger.